Macular Degeneration
Age related macular degeneration (AMD) is an age-related eye disease which affects the central portion of the retina - the macula.
There are two main subtypes of AMD – dry and wet. Dry AMD is caused by wear and tear of the cells in the macula. Wet AMD is caused by abnormal blood vessels which leak into the delicate layers of the central retina.
Both wet and dry AMD cause distortion (especially distortion of straight lines) or loss of central vision. If you experience these symptoms, you should contact your optometrist urgently.
The main risk factors for AMD are increasing age, smoking and UV exposure. Food or dietary supplements containing lutein and xanthin are recommended to promote macular health.
What is dry AMD?
Dry AMD is caused by damage to the photo receptor cells in the retina. These cells are continuously ‘recycled’ after use and this process slows with age. Waste products from the recycling process, called drusen, accumulate in the retina. In small amounts this may not cause a significant change to vision, but larger accumulations of drusen can cause central vision to become distorted or blurry. In eyes with advanced dry AMD, scarring can form which can cause more severe central vision loss. Normally, dry AMD progresses slowly and vision changes are gradual.
What is the treatment for dry AMD?
Unfortunately, there is no treatment for dry AMD and no way to reverse any changes once they have occurred.
What is wet AMD?
Wet AMD is caused by abnormal blood vessels growing into the macula from the structure underneath the retina called the choroid. These blood vessels are weak and can leak within the retina causing fluid to accumulate. This causes the retina to swell and central vision to become wavy or distorted. The accumulation of fluid prevents the macula from functioning normally and eventually scar tissue can develop. Compared to dry AMD, vision changes with wet AMD tend to be more sudden and severe.
What is the treatment for wet AMD?
Often, injections of special drugs into the eye can reduce abnormal blood vessel growth and prevent blood vessels leaking. Usually, the aim of this treatment for wet AMD is to prevent vision from getting worse but occasionally vision can improve with this medication.
How can AMD be detected?
Your optometrist will assess the health of the retina, including the macula, at every routine eye examination. In addition to looking directly into the eye they may be able to use OCT scans which produce 3D images of all the layers of the retina allowing the deeper layers of the macula to be assessed in greater detail.
For more information, please see https://www.nhs.uk/conditions/age-related-macular-degeneration-amd/